Time Scale of Scouring Around Submarine Pipelines Induced by Wave and Current

Physical experiments have been conducted to explore the time scale of the wave- and current- induced local scouring around submarine pipelines as well as the development of the scour profile versus the elapsing time. The experimental results have been used to examine the recommended equations of Fredsoe et al. (1992) and/or to derive new equations for prediction of scour depth/width during the process with respect to the equilibrium scour properties. In addition, the total duration (time scale) of scouring is studied and a new equation is proposed for the case of current motion. The results of this equation are then simplified in the form of diagrams for estimation of the scouring duration in practice.